Parts
$20–80
P0354 — Ignition Coil D Primary/Secondary Circuit
CAUTIONIs it safe to drive? Cylinder D is likely dropping combustion events — drivable short-term, but address it before the misfire damages the catalytic converter.
What P0354 means
The ECM expected a normal coil firing signal from Coil D and didn't get one. On most inline-4 engines coil D is the last cylinder in the firing order — easy to reach but sometimes hidden under a plastic cover.
Most likely causes (in order)
- Coil-on-plug unit or coil pack for cylinder D
- Spark plug fouled, cracked, or wrong heat range
- Connector or wiring fault
- Oil contamination on plug from leaking valve cover gasket
- ECM output driver (last resort diagnosis)
Symptoms you might notice
- rough idle
- single-cylinder misfire feel
- poor acceleration
- CEL flashing
What to check first
Inspect the cylinder D spark plug well for oil — a wet well means the valve cover gasket is leaking and soaking the boot and plug, which kills coils repeatedly. Fix the gasket before replacing the coil or you'll buy another one in a year.
Repair cost & difficulty
Labor
0.5–1 hr
Difficulty
Easy DIY